With her pooch in tow, the Gossip Girl star celebrates her 21st b-day on the New York City set of her show. Plus: Ashlee Simpson, Lindsay Lohan, Paris Hilton and more
Credit: Jason LaVeris/FilmMagic
Published: Monday Aug 25, 2008 | 05:50 PM EDT
More from PEOPLE
- RHOA Reunion: Did Apollo Ever Get Physical with Phaedra?
- Daytime Emmys Awards 2015: And the Winners Are ...
- Game of Thrones Recap: 'High Sparrow'
- KUWTK: Rob Says Scott's Drunken Antics Have Him Acting 'Crazy'